Temporomandibular joint dysfunction (
TMD, 
TMJ, 
TMJD), also known as 
temporomandibular joint dysfunction syndrome and 
temporomandibular disorder among others,[SUP]
[1][/SUP] is an 
umbrella term covering 
pain and dysfunction of the 
muscles of mastication (the muscles that move the jaw) and the 
temporomandibular joints (the joints which connect the 
mandible to the 
skull). The most important feature is pain, followed by restricted mandibular movement,[SUP]
[2][/SUP]  and noises from the temporomandibular joints (TMJ) during jaw movement.  Although TMD is not life-threatening, it can be detrimental to 
quality of life,[SUP]
[3][/SUP] because the symptoms can become chronic and difficult to manage.
 TMD is a symptom complex rather than a single condition, and it is thought to be caused by multiple factors.[SUP]
[4][/SUP][SUP]
[5][/SUP] However, these factors are poorly understood,[SUP]
[6][/SUP] and there is disagreement as to their relative importance. There are many treatments available,[SUP]
[7][/SUP]  although there is a general lack of evidence for any treatment in TMD,  and no widely accepted treatment protocol. Common treatments include  provision of occlusal splints, psychosocial interventions like 
cognitive behavioral therapy, and 
pain medication or others. Most sources agree that no irreversible treatment should be carried out for TMD.[SUP]
[8][/SUP]